The German Amateurs Who Discovered ‘Insect Armageddon’

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Thomas Hörren, a member of the Entomological Society Krefeld, collecting beetles from a soil sample.CreditGordon Welters for The New York Times

By Sally McGrane

Dec. 4, 2017

KREFELD, Germany — In a nature preserve in western Germany, an elderly gentleman approached a tent-like structure that was in fact a large trap for flying insects. Peering through thick eyeglasses, the 75-year-old retired chemist checked the plastic bottle attached at the top, filled with alcohol and bugs.

Then, with a glance at the clear, late-autumn sky, the man, Heinz Schwan, recalled comparing a 2013 haul from a trap like this one to samples taken in the same place some 20 years earlier. The drop was huge: “75 percent,” Mr. Schwan, a caterpillar lover, said.

Alarmed, the group of local insect enthusiasts Mr. Schwan is co-chairman of ran similar tests in different locations the next year. And the next year. And the next.

Now their findings have been made public. The news shot around the world, eliciting headlines about “insect Armageddon.” The insect populations they tested had declined by more than 75 percent over the last three decades, explaining why, these days, car trippers no longer need to clean bugs from the windshield.

Lost in the flurry was the source of the news — the obscure, volunteer-run Entomological Society Krefeld, tucked away in western Germany near the Dutch border.

That a group composed not just of biology Ph.D.s but also chemists, electrical engineers, a schoolteacher and a physicist, among others, would be the ones to do such groundbreaking research did not surprise Dave Goulson, a bee expert at the University of Sussex, and co-author of a scientific article based on the group’s research and published this fall.

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The all-volunteer society shocked the world by documenting a 75 percent drop in flying insect populations.CreditGordon Welters for The New York Times

“In this field, amateurs are often the experts,” he said. “Most people don’t really pay attention to insects. With the exception of butterflies, because they’re pretty.”

Bugs have long gotten short shrift, scientifically. Estimated to make up more than half of all animal life, only about 10 percent of insect species are thought to have even been named.

In addition, raw data about the creatures is hard to come by. “This kind of monitoring is unspectacular, so it usually doesn’t get done,” said Teja Tscharntke, a professor of agro-ecology at the University of Göttingen. “That’s where the hobbyists from Krefeld come in.”

Their study looks at 63 nature preserves mostly in the area around Krefeld. But experts say it is likely to reflect the insect situation in places like North America, where monoculture and pesticide use are widespread.

“People have been saying, ‘There just doesn’t seem to be as many ‘X’ as there used to be,’” said Steve Heydon, senior scientist at the University of California, Davis’s Bohart Museum of Entomology, of the Krefeld study. “It’s nice to have it documented. Figures change it from an opinion to a fact.”

Mr. Tscharntke agreed. “I was a little surprised, but it fits with what we know about, say, insect-eating birds disappearing,” he said.

Calling the Krefelders’ data “a rich treasure trove,” Mr. Tscharntke warned that entomology hobbyists are themselves a dying species. “These days, people who spend their free time looking at ladybugs and flies are about as common as stamp collectors.”

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Members of the society use traps installed all over western Germany to track insect populations.CreditGordon Welters for The New York Times

In Germany and around the world, members of entomological societies tend to be elderly. And, in a field that has seen very little in the way of high-tech digitization, their expertise often dies with them.

In many ways, the Krefelders buck these trends. For one thing, the society, which is more than 100 years old, is keen on archiving.

“In a lot of places, everything gets thrown out — the papers, the insect collection,” said Martin Sorg, a longstanding member of the Krefeld society whose expertise includes wasps.

Gesturing around the group’s book-lined headquarters, Mr. Sorg said things were different, here. “When one of our members dies, we keep everything, even handwritten notes.”

They also focus on the future. About a third of the society’s 59 members are newbies, and children as young as 12 can join the society’s adults in poring over unsorted trays of translucent wings and delicate thoraxes, or carefully rifle through the wooden cabinets that hold over a million pinned wasps, bees, ants, sawflies, beetles, flies, mosquitoes, butterflies, moths, dragonflies, crickets, true bugs, lacewings and caddis flies.

Experienced entomologists take beginners on expeditions, and train them in the complex art of identifying insects. “Knowledge is passed down, from one generation to the next,” said Thomas Hörren, who is 28 and wears a large tattoo of his favorite insect, the beetle, on his neck. “Growing up, there was nobody to guide me.”

Krefeld’s youngest official member is 14. “He’s an ant guy,” said Mr. Schwan, himself a childhood bug lover. It was not until his late 20s that he discovered Krefeld’s entomological society and started learning about caterpillars.

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The society maintains meticulous records.CreditGordon Welters for The New York Times

Back then, members, along with their bugs, met every two weeks at Krefeld pubs.

Gazing into a glass-covered box of ants, Mr. Schwan smiled and said he planned to take the teenager and the ants along to an coming entomological conference in Düsseldorf. There, an ant expert from Wuppertal promised to identify the boy’s specimens.

Harald Ebner, a pesticide expert and politician with Germany’s Green Party, said it was “typically German” for people to spend free time doing club-based volunteer work.

“Without the efforts of the Krefeld insect researchers, we would only have the observation that, these days, your car’s windshield is almost totally free of insects,” wrote Mr. Ebner, in an email. “On the other hand, the lack of interest on the part of the state is horrifying, especially in a country where just about everything else is so precisely tested, overseen and counted.”

But Josef Tumbrinck, a society member who works as an environmental lobbyist, thinks the plight of insects is going to interest a wider audience soon.

“Right now, it’s ‘those nutty entomologists,’” Mr. Tumbrinck said. “But I think this is going to get more and more attention, not just from crazy people with long hair.”

Setting a glass box down on the table, he pointed to a hand-size butterfly that his wife hatched from eggs for the school where she teaches. Mr. Tumbrinck’s 10-year-old son tugged on his sleeve. “And I found this one in the lamp,” he whispered, pointing to a little gray moth mounted next to it.

As the scent of 82 proof alcohol that preserves the bugs wafted, just a little, through the room, a reporter asked if, at this rate, all the insects were going to disappear.

“Oh, don’t worry,” said Mr. Sorg, the wasp expert. “All the vertebrates will die before that.”

A version of this article appears in print on , on Page A8 of the New York edition with the headline: The Germans Who Discovered ‘Insect Armageddon’. Order Reprints | Today’s Paper | Subscribe